Algorithm 3. Substitution of Cluster Head

/*Substitution of the cluster head vIDi on a cluster node vx*/ TVIDi = TVIDi − 0.2; if (TVIDi < TTv && NAIDi < Nc/2) {  Broadcast an ALARM message for vIDi;  vx, and each cluster node that hears the ALARM message, executes Algorithm 2; } Reset the timer TRG; Select the trusted non-participating cluster node, whose ID is closer to hv than the others (vt for example), to substitute vIDi; Select the current participating node whose ID is closest to hv (vm for example) as the new CH; if (vx is exactly vm) {  if (vt does not provide ktP)   Perform the proposed substitution scheme in Step 5;  else {// vx has stored the kjP of the other participating nodes when they sent kjP to vIDi.   Compute R and broadcast X(R);   Receive and verify each new σj;   if (some current participating nodes do not provide their new σj or provide incorrect σj)    Perform the proposed substitution scheme in Step 5;  } } else if (vx is exactly vt) {  Pick kx in [1, q − 1] and send kxP to vm;  Compute σx after receiving X(R) from vm;  Send σx to vm; } else if (vx is a participating node that has not been substituted) {  Recompute σx after receiving X(R) from vm;  Send σx to vm; }